ISTQB Certified Tester Foundation Level v4.0 — Question 72

You validate the correctness of price calculation in a food ordering application. The input parameter is the order amount (in $), and the result is the final price reflecting the discount. If the order amount is less than $100, the discount is not granted (0% discount). If the order amount is greater than $500, a 50% discount is granted. In other cases, the 10% discount is granted.

You apply equivalence partitioning for the “order amount” domain to check if discounts are granted correctly.

Which test data set achieves the highest coverage?

Answer options

• A. 100.01, 499.99, 500.01
• B. 50.99, 500, 500.10
• C. 99.99, 100, 500
• D. 0, 10, 50

Correct answer: B

Explanation

Option B is correct because it includes a value under $100 (50.99), a value at the threshold for a 50% discount (500), and a value just over that threshold (500.10), thus covering all relevant discount scenarios. The other options do not provide a complete representation of the discount thresholds, either missing the critical boundaries or being outside the valid range.